1. Field of the Invention
The present invention generally relates to optical guide apparatuses and, more particularly, is directed to an optical guide apparatus or an optical guide end-fire (transversal) coupling apparatus for making a laser beam of a fundamental wave be incident on an optical guide device having an optical guide such as an optical guide type secondary harmonic generator (SHG).
2. Description of the Related Art
In the optical guide device having an optical guide such as an optical guide SHG, a waveguide mode type SHG a Cherenkov radiation type SHG, or the like, with respect to an incident laser light, for example, the fundamental wave of the incident light on the optical guide is very important.
Namely, since the power Pw of the secondary harmonics generated by the SHG, for example, is proportional to the square of the power Pw of the incident light wave, it is very important to make the incident light be incident in the optical guide with a high efficiency,
Further, the output light quantity of the optical guide is greatly influenced by the fluctuation of the incident light power, that is, the fluctuation of the light quantity being incident on the optical guide.
Furthermore, in this type of optical guide device, its optical source unit, particularly, its condenser lens system (object lens system) is generally fixedly mounted on the optical guide apparatus by a bonding agent in a state that it is positioned relative to an end facet of the optical guide device. Thus, if the condenser lens system is deviated from its correct position due to vibration applied thereto or a change in ambient temperature or the like, the apparatus becomes inoperable in use.